Gum inhibitor for cracked hydrocarbons



Patented June 12, 1934 UNITED STATES PATENT OFFICE GUM INHIBITOR FORCRACKED HYDROCARBONS No Drawing. Application September 26, 1930, SerialNo. 484,703

6 Claims.

This invention relates to improvement in means I for the stabilizationof mineral hydrocarbon products. More particularly it relates to theutilization of organic compounds as addition products for substances ofthe class named. The tendency of liquid hydrocarbons to discolor and toform gum, sludge and resinous substances is at present the bte noire ofall persons connected with their production,-distribution and use.

Gasolines, for example, as produced by the modern cracking processes areextremely complicated mixtures comprising many constituents. Thecharacter ofthese constituents and the relative proportions of eachdepend upon the source of the crude petroleum and the particularcracking process employed. Ordinarily substantial percentages ofunsaturated aliphatic and aromatic hydrocarbons are present. In certaininstances these percentages are intentionally increased by the additionof unsaturated compounds to gasolines. Such additions may also be madeto gasolines not containing unsaturated hydrocarbons. Regardless of howproduced, gasolines containing these unsaturated compounds form, in -thepresence of air, a series of products some of which are resinous orgummy. These gums or resins form sticky substances which deposit on thewalls and bottom of the container in which the gasolines are stored andin some instances discolor the gasoline. Certain portions of the gumsformed may be soluble in the gasoline but they are also objectionablebecause of the consequent introduction of non-volatile components intothe gasoline. Exposure to sunlight causes discoloration which in someinstances is accompanied by appreciable gumming.

Similar problems or disadvantages are encountered with motor benzolwhich is the name applied to amaterial similar to gasoline in physi. calproperties but which consists largely of aromatic or unsaturatedhydrocarbon compounds. In transformer oil such as used in the electricalindustry, these materials are detrimental in that a sludge tends to formin the transformer oil container and interferes with the satisfactoryop:-

eration of such apparatus.

In the past it has been necessary to tolerate these disadvantages or totreat the crude products resulting from the more recent oil treatingprocesses in some manner to remove the greater part of these unsaturatedproducts.

This invention has for an object the inhibition or retardation of theformation of insoluble gums and resins in mineral hydrocarbons. Furtherobjects are to prevent discoloration of the same compounds, to makepossible the distribution and use of hydrocarbon motor fuels which arefree from gum and to prevent gum formation in more highly crackedgasolines which would otherwise develop excessive amounts of gum and.thereby be 30 rendered unfit for ordinary use.

Still further objects are to make it possible to use as an internalcombustion fuel liquid hydrocarbons such as gasoline that contain largeramounts of unsaturated compounds than commercially used at present, toproduce a product of this sort at lower cost and to produce one which incertain instances possesses improved antiknockproperties. Other objectswill appear hereinafter.

These objects are accomplished by the present invention whereby a memberor members of the group comprising di-hydroxy naphthalenes andpara-hydroxy-phenyl glycine are added in small quantities to crackedhydrocarbons. The invention Will be readily understood from aconsideration of the examples which follow in which the parts are givenby weight.

One of the tests used for evaluating the effectiveness of this class ofcompounds as stabilizers 89 or gum inhibitors is the accelerated oxygentest.

In this test twenty-five (25) cc. of motor fuel, cracked gasoline, motorbenzol, or the like, treated with 0.001 to 1% of the stabilizing agentare heated at 100 C. in an atmosphere of oxygen for 3 to 6 hours. Thegum formed is measured by evaporating the hydrocarbon after the oxygentest from a porcelain dish in the steam oven. The extent of gumformation during the accelerated oxygen test is a measure of thestability and gumming tendency of the fuel during the long time storage.

Example I Cracked gasoline treated with 0.02% 1:5-dihydroxy-napht halenegave 16 mg. gum per 25 co. in the accelerated oxygen gum test run forfive and one-half hours. The gum formed in the same gasoline, but notstabilized, under the same conditions was mg. per 25 cc.

Example II treated. As specific examples,..=mention may be the aboveexamples. Use may be made of higher or lower concentrations of anymember of the groups of compounds disclosed above and as a resultthereof greater or less inhibition of gum formation and prevention ofdiscoloration secured depending upon the. specific agent used,

the solubility of the agent, the concentration of the agent, the natureof the material treated and the conditions under which the treatment andsubsequent storage take place.

agent may vary between the limits of 0.001 to 1.0%. It will be apparent,however, that this range is not given as limiting since lesser orgreater amounts may be used in specific instances within the scope of'the invention; In

most instances no marked advantage is gained by using more than themaximum amount set out above. In any event the range given appears to besufficient for the grades of gasoline and oils of similarcharacteristics now on the market.

.In' general all mineral hydrocarbons may be vided into several groupsas follows:

IDihydroxynaphthalenes, such as-- (1) 1 2-dihydroxy-naphthalene (2) 1:4-dihydroxy-naphthalene (3) 1 7-dihydroxy-naphthalene (4) 2:3-dihydroxynaphthalene The pre-l ferred actual concentration of the stabilizingII-Para-hydroxy-phenyl-glycine (5) It is to be understood that otherisomers and homologues in the classes mentioned above may rbe used. Incertain cases it has been found advantageous to use two or more of thespecific compounds covered by this invention. It will be appreciatedthat the examples outlined above and the specific compounds mentionedare given merely for the purpose of illustrating and not for limiting,the invention.

Obviously this invention is of great importance in freeing internalcombustion engines from the annoyance and improper functioning due tothe deposition of gum in the fuel containers or fuel systems.

As many apparently widely diiferentexnbodimerits of this invention maybe made without departing from the spirit and scope thereof, it is to beunderstood that we do not limit ourselves to the specific embodimentsthereof except as defined in the appended claims.

We claim:

1. Motor fuel comprising cracked hydrocarbon spirits normally tending toform gum having incorporated therein a para-hydroxyphenyl-glycine inanamount sufiicient to inhibit the formation of gum therein.

2. Motor fuel comprising cracked hydrocarbon spirits normally tending toform gum having incorporated therein about 0.001 to 0.1% of aparahydroxy-phenyl-glycine.

3. Motor benzol comprising cracked hydrocarbon spirits normally tendingto form gum having incorporated therein a para-hydroxy-phenylglycine inan amount sufficient to inhibit the formation of gum therein.

4. Motor benzol comprising cracked hydrocarbon spirits normally tendingto form gum having incorporated therein about 0.001 to 0.1% of apara-hydroxy-phenyl-glycine.

5. Cracked gasoline normally tending to form gum having incorporatedtherein a para-hydroxy-phenyl-glycine in an amount suflicient to inhibitthe formation of gum therein.

6. Cracked gasoline normally tending to form gum having incorporatedtherein about 0.001 to 0.1% of a para-hydroxy-phenyl-glycine.

FREDERICK B. DOWNING. HERBERT w. WALKER.

